# US 2014/0191604 A1 · Mechanical backup bearing arrangement for a magnetic bearing system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0191604 A1 - Document ID: US20140191604A1 - Status: Published application - Kind: A1 - Application number: 13/735,468 - Filed: 2013-01-07 - Published: 2014-07-10 - Earliest claimed: 2013-01-07 - Assignees: Calnetix Technologies, LLC - Inventors: Lawrence A. Hawkins; Alexei Filatov - Web page: https://patentgrep.com/patent/US20140191604A1 ## CPC - H02K 7/09: with magnetic bearings - F16C 32/0442: {with devices affected by abnormal, undesired or non-standard conditions such as shock-load, power outage, start-up or touchdown} - F16C 39/02: using mechanical means - H02K 5/1732: {radially supporting the rotary shaft at both ends of the rotor (H02K5/1737 takes precedence)} - H02K 7/083: {radially supporting the rotary shaft at both ends of the rotor (H02K7/086, H02K7/09 take precedence)} - H02K 2213/06: Machines characterised by the presence of fail safe, back up, redundant or other similar emergency arrangements - Y10T 29/49009: Dynamoelectric machine - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) - F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract The present disclosure describes a mechanical backup bearing system arrangement to work in conjunction with non-contact magnetic bearings and capable of coping with thermal expansions of the bearing components during operations. Expansions or contractions of an inner or outer race of a bearing can be compensated using particular springs providing a low profile and a proper stiffness. An electric machine system includes a rotational portion and a stationary portion. The electric machine further includes a magnetic bearing configured to support the rotational portion to rotate within the stationary portion. A mechanical back-up bearing resides in a cavity between the rotational portion and the stationary portion. A flat spring is carried by the stationary portion and abutting the back-up bearing. ## Claims ### Claim 1 An electric machine system comprising: a rotational portion and a stationary portion; a magnetic bearing configured to support the rotational portion to rotate within the stationary portion; a mechanical back-up bearing residing in a cavity between the rotational portion and the stationary portion; and a flat spring carried by the stationary portion and abutting the back-up bearing. ### Claim 2 (depends on 1) The electric machine system of claim 1, wherein the back-up bearing further comprises: an inner backup bearing race that comes in contact with the rotational portion when the rotational portion is not supported by the magnetic bearing; and an outer backup bearing race carried by the stationary portion, the outer race and the inner race encasing backup bearing balls; and wherein the flat spring contacts the lateral side of the outer race. ### Claim 3 (depends on 2) The electric machine system of claim 2, wherein the flat spring is configured to deflect upon an axial movement of the lateral side of the outer race. ### Claim 4 (depends on 2) The electric machine system of claim 2, wherein the flat spring applies a preloaded force to the outer race. ### Claim 5 (depends on 1) The electric machine system of claim 1, further comprising a retainer clamping the flat spring against the stationary portion, wherein the retainer is separated from at least a portion of the flat spring by an air gap. ### Claim 6 (depends on 5) The electric machine system of claim 5, wherein the flat spring is configured to deflect towards the air gap upon thermal expansion of the inner race of the back-up bearing. ### Claim 7 (depends on 6) The method of claim 6, wherein the retainer is a hard stop for deflection of the flat spring upon thermal expansion of the inner race. ### Claim 8 (depends on 1) The electric machine system of claim 1, wherein the stationary portion comprises an end housing, and wherein the flat spring is carried by the end housing and supported against the end housing by a shim. ### Claim 9 (depends on 1) The electric machine system of claim 1, wherein the flat spring comprises a flat circular disk with a central hole. ### Claim 10 (depends on 1) The electric machine system of claim 1, wherein the flat spring comprises a plurality of radial slots. ### Claim 11 (depends on 1) The electric machine system of claim 1, wherein the back-up bearing is a duplex bearing. ### Claim 12 A method comprising: supporting a rotational portion of an electric machine without a mechanical contact using magnetic bearings under normal operating conditions; supporting an outer race of a back-up bearing on a stationary portion of the electric machine; positioning an inner race of the back-up bearing in a close proximity of the rotational portion of the electric machine so that the rotational portion of the electric machine comes into contact with the inner race; and clamping a flat spring on the outer race of the back-up bearing at a preloaded force, the flat spring being configured to deflect upon axial motion of the outer race. ### Claim 13 (depends on 12) The method of claim 12, further comprising supporting the flat spring using a retainer against a lateral surface of the outer race, wherein the retainer is separated from at least a portion of the flat spring by an air gap. ### Claim 14 (depends on 13) The method of claim 13, wherein the flat spring is configured to deflect towards the air gap upon thermal expansion of the inner race. ### Claim 15 (depends on 13) The method of claim 13, wherein the retainer is a hard stop for deflection of the flat spring upon thermal expansion of the inner race. ### Claim 16 (depends on 15) The method of claim 15, wherein a shaft is coupled with a rotor of the electric machine. ### Claim 17 (depends on 12) The method of claim 12, further comprising applying a pre-load compression to the lateral surface of the outer race with the flat spring. ### Claim 18 (depends on 12) The method of claim 12, further comprising creating a space with a shim between the flat spring and an end housing, wherein the flat spring is carried by the end housing and supported against the shim. ### Claim 19 (depends on 12) The method of claim 12, wherein the bearing system is a backup bearing of an electric machine.